Conventionally, there is known a lighting circuit configured to generate a PWM dimming signal corresponding to an emission level specified by a dimming signal, and perform the dimming control by using a light emitting element such as an organic EL element.
For example, Japanese Patent Application Publication No. 2011-60703 discloses a lighting circuit configured to perform a so-called burst dimming to stop the emission of the light emitting element during an OFF period of the PWM dimming signal.
The light emitting element such as an organic EL element having a diode characteristic begins to emit a light when an applied voltage exceeds a threshold voltage Vth. In the burst dimming performed by the apparatus described in Japanese Patent Application Publication No. 2011-60703, the emission of the light emitting element is completely stopped during the OFF period of the PWM dimming signal. Since there is a significant variation in the threshold voltage Vth of the light emitting element due to a manufacturing error, lighting timings of different light emitting elements may not the same when the PWM dimming signal is switched to a next ON period.